US4128779A - Stranded conductor for dynamoelectric machines - Google Patents

Stranded conductor for dynamoelectric machines Download PDF

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Publication number
US4128779A
US4128779A US05/784,753 US78475377A US4128779A US 4128779 A US4128779 A US 4128779A US 78475377 A US78475377 A US 78475377A US 4128779 A US4128779 A US 4128779A
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United States
Prior art keywords
bars
conductor
strands
bar
stacks
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/784,753
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English (en)
Inventor
Sheppard J. Salon
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US05/784,753 priority Critical patent/US4128779A/en
Priority to BE186294A priority patent/BE865349A/fr
Priority to JP3693178A priority patent/JPS53123801A/ja
Application granted granted Critical
Publication of US4128779A publication Critical patent/US4128779A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/12—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors arranged in slots
    • H02K3/14—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors arranged in slots with transposed conductors, e.g. twisted conductors

Definitions

  • the present invention relates to a winding conductor for dynamoelectric machines, and more particularly to a transposed, stranded conductor of high current capacity for use as a winding conductor or half-coil for machines of large size, such as turbine generators.
  • the winding conductors of large dynamoelectric machines are placed in slots in a laminated magnetic stator core.
  • Each conductor, or half-coil has a straight portion disposed in the slot and end portions which extend around the circumference of the core for connection to other conductors lying in different slots to form complete coils.
  • the magnetic fluxes which occur across the slots cause induced voltages and eddy currents in the conductors, and for this reason the conductors of large machines are always of stranded construction, being built up of a substantial number of relatively thin strands to minimize the eddy current loss.
  • each strand is disposed in two side-by-side stacks and transposed within the slot by crossovers between the stacks. That is, the strands are inclined in each stack so that each strand moves radially to the top or bottom of the stack, crosses over to the other stack, moves radially through the stack, and crosses over back to the first stack.
  • each strand moves through an angle of 360° in going from one end of the slot to the other, and emerges in the same relative position at which it entered the slot.
  • Each strand therefore, occupies all positions in the slot for equal distances and the induced strand voltages are exactly balanced within the slot. Induced strand voltages also occur in the strands in the end portions of the conductor outside the slot, however, and in the usual practice these have been taken care of by the group transpositions between groups of strands at the connections between the ends of adjacent conductors, so that these voltages are balanced out within a complete coil or group of coils.
  • a winding conductor for large dynamoelectric machines which utilizes two stranded and transposed conductor bars arranged in parallel in the slot and connected together at the ends.
  • the voltages induced by radial fluxes result in a seriously unequal distribution of current between the two bars, as discussed above, but the adverse thermal effects of this unequal current distribution are eliminated by making the two bars of unequal cross-sectional area. That is, one bar is of greater transverse width than the other bar so that the total cross-sectional areas of copper in the two bars are not equal and are substantially proportional to the currents flowing in the bars.
  • the current is unequally divided between the two bars of each conductor but because of the difference in area, the current density is essentially the same in both bars. More heat is generated in one bar than in the other but it is distributed throughout a greater volume of copper, so that the temperature rise is kept the same in both bars and the normal cooling means can be used.
  • the increased cross-sectional area of one bar relative to the other is easily provided by using wider strands in one bar than in the other so that the total cross-section of copper in each bar meets the requirement indicated above.
  • FIGS. 1 and 2 are a top view and a side view, respectively, of a single transposed conductor bar
  • FIG. 3 is a transverse sectional view of a complete conductor embodying the present invention.
  • the invention relates in particular to winding conductors for turbine generators of large size where the load currents to be carried are such that four stacks of strands are required.
  • Two conductor bars with two stacks of strands in each bar are used for this purpose, but when two such bars are paralleled, the circulating currents cause serious overheating of one bar even when 540° transpositions are used. This is due to the radial fluxes in the machine which cause unbalanced voltages between the two bars such that very large circulating currents flow between the bars and are superimposed on the normal load current.
  • These circulating currents can be of the order of 20% to 30% of the maximum load current and typically result in a distribution of the total current between the two bars such that one bar carries 60% of the current and the other bar only 40%.
  • each of the conductor bars is made up of two stacks of strands which are transposed between the stacks, and where the conductors are solidly connected together at both ends so that all stacks of strands in both bars are in parallel, as in liquid-cooled machines, it is preferred to use transposed conductor bars 10 of the type shown in the above-mentioned Brenner patent.
  • transposed conductor bars 10 of the type shown in the above-mentioned Brenner patent.
  • such a conductor bar consists of a plurality of relatively thin strands 12 arranged in two side-by-side stacks, at least some of the strands being hollow for circulation of liquid coolant, or other known cooling means being provided.
  • the strands 12 are transposed between stacks in a manner generally similar to the conventional Roebel transposition by crossovers indicated at 14.
  • the strands are, however, transposed through 540°, that is, the strands are transposed through 180° in the first one-fourth of the slot length of the bar, through another 180° in the second and third quarter length of the bar, and another 180° in the fourth quarter of the bar length, the crossover spacing being adjusted as necessary in the different sections of the bar.
  • the strands in the end portions 15 at opposite ends therefore, are inverted in relative position to at least partially cancel the unbalanced end portion voltages.
  • untransposed sections 16 of suitable length are provided at appropriate points within the slot portion of the bar, as more fully explained in the Brenner patent, to obtain substantially complete compensation of induced strand voltages. While this is the preferred type of conductor bar, it will be understood that the invention is not limited to this particular arrangement, and that any suitable stranded and transposed conductor bar could be used which is suitable for connection in parallel with another similar bar.
  • a non-symmetrical conductor consisting of two parallel bars 20 and 21 as shown in FIG. 3. These bars are similar to the bars 10 of FIGS. 1 and 2, and each bar consists of a plurality of strands 12 disposed in two stacks and transposed from stack-to-stack as previously described.
  • the two bars 20 and 21 are arranged side-by-side and insulated from each other as indicated at 24.
  • the complete conductor is enclosed in the usual high voltage ground insulation 25.
  • the conductor thus consists of two stranded bars disposed physically and electrically in parallel.
  • the conductor is intended to be placed in a slot 26 in the stator core 27 of a large generator.
  • the two bars 20 and 21 of each conductor are different in size. That is the total cross-sectional area of copper is different in the two bars, and preferably is made substantially proportional to the expected current in each bar. Thus, if the division of current between the two bars is in the ratio of 60:40, as discussed above, then the total copper cross-sectional area is also in the ratio of 60:40 as illustrated in FIG. 3.
  • the increased copper cross-section of one bar as compared to the other can be obtained in any desired manner in designing the bar. It is preferred as shown in FIG. 3 to use wider strands in the bar 20 than in the bar 21, the thickness of the strands remaining the same so that the same number of strands can be used in both bars and both stacks are of the same height. This may slightly increase the local eddy current loss due to radial flux in the top few strands of the bar 20, but this is a very small effect which does not seriously affect the cooling. It will be seen, therefore, that a conductor has been provided having four stacks of strands but without the serious heating problem which results from merely paralleling two identical conventional conductor bars.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Windings For Motors And Generators (AREA)
US05/784,753 1977-04-05 1977-04-05 Stranded conductor for dynamoelectric machines Expired - Lifetime US4128779A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US05/784,753 US4128779A (en) 1977-04-05 1977-04-05 Stranded conductor for dynamoelectric machines
BE186294A BE865349A (fr) 1977-04-05 1978-03-28 Conducteur lamelle pour machines dynamoelectriques
JP3693178A JPS53123801A (en) 1977-04-05 1978-03-31 Winding conductor for rotary electric machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US05/784,753 US4128779A (en) 1977-04-05 1977-04-05 Stranded conductor for dynamoelectric machines

Publications (1)

Publication Number Publication Date
US4128779A true US4128779A (en) 1978-12-05

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US05/784,753 Expired - Lifetime US4128779A (en) 1977-04-05 1977-04-05 Stranded conductor for dynamoelectric machines

Country Status (3)

Country Link
US (1) US4128779A (fr)
JP (1) JPS53123801A (fr)
BE (1) BE865349A (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4260924A (en) * 1978-09-27 1981-04-07 Westinghouse Electric Corp. Conductor bar for dynamoelectric machines
US4337567A (en) * 1978-09-27 1982-07-06 Westinghouse Electric Corp. Method of making a conductor bar for dynamoelectric machines
US5323079A (en) * 1992-04-15 1994-06-21 Westinghouse Electric Corp. Half-coil configuration for stator
US20020088384A1 (en) * 2000-08-03 2002-07-11 Frederick Bernhardt Method of manufacturing a liner sock for use between a limb prosthesis and a limb liner
US20040012290A1 (en) * 2002-07-19 2004-01-22 Worley Andrew C. Electric motor and generator component having a plurality of windings made from a plurality of individually conductive wires
US6703752B2 (en) * 2000-11-27 2004-03-09 Alstom Technology Ltd Stator winding bar for an electrical machine
US20050116573A1 (en) * 2003-11-28 2005-06-02 Hitachi, Ltd. Armature windings and dynamo-electric machine using the same
US20050168096A1 (en) * 2004-02-02 2005-08-04 Alstom Technology Ltd Method for producing a conductor bar of transposed stranded conductors
US20090127966A1 (en) * 2007-11-15 2009-05-21 Juha Saari Stator winding method and apparatus
EP2262079A1 (fr) * 2009-06-08 2010-12-15 Alstom Technology Ltd Barre d'enroulement de stator en forme de barre Roebel avec des têtes de bobines transposés
US10510464B1 (en) * 2017-12-20 2019-12-17 Essex Group, Inc. Continuously transposed conductors and assemblies

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0617381U (ja) * 1992-07-31 1994-03-04 松下電器産業株式会社 ステッピングモータの固定子

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1169012A (fr) * 1955-12-24 1958-12-19 Siemens Ag Barre conductrice composée pour machines à courant alternatif
US2896102A (en) * 1957-03-04 1959-07-21 Mc Graw Edison Co Electrical conductor and process for making same
US3188377A (en) * 1962-06-08 1965-06-08 Gen Electric Armature bar transposition
US3280244A (en) * 1962-07-18 1966-10-18 Licentia Gmbh Transposed conductor bar
US3381154A (en) * 1964-04-08 1968-04-30 Asea Ab High power synchronous machine
US3647932A (en) * 1970-12-11 1972-03-07 Westinghouse Electric Corp Transposed conductor for dynamoelectric machines
USRE27489E (en) 1972-01-11 1972-09-26 Transposed conductor for dynamoelectric machines

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1169012A (fr) * 1955-12-24 1958-12-19 Siemens Ag Barre conductrice composée pour machines à courant alternatif
US2896102A (en) * 1957-03-04 1959-07-21 Mc Graw Edison Co Electrical conductor and process for making same
US3188377A (en) * 1962-06-08 1965-06-08 Gen Electric Armature bar transposition
US3280244A (en) * 1962-07-18 1966-10-18 Licentia Gmbh Transposed conductor bar
US3381154A (en) * 1964-04-08 1968-04-30 Asea Ab High power synchronous machine
US3647932A (en) * 1970-12-11 1972-03-07 Westinghouse Electric Corp Transposed conductor for dynamoelectric machines
USRE27489E (en) 1972-01-11 1972-09-26 Transposed conductor for dynamoelectric machines

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4337567A (en) * 1978-09-27 1982-07-06 Westinghouse Electric Corp. Method of making a conductor bar for dynamoelectric machines
US4260924A (en) * 1978-09-27 1981-04-07 Westinghouse Electric Corp. Conductor bar for dynamoelectric machines
US5323079A (en) * 1992-04-15 1994-06-21 Westinghouse Electric Corp. Half-coil configuration for stator
US20020088384A1 (en) * 2000-08-03 2002-07-11 Frederick Bernhardt Method of manufacturing a liner sock for use between a limb prosthesis and a limb liner
US6703752B2 (en) * 2000-11-27 2004-03-09 Alstom Technology Ltd Stator winding bar for an electrical machine
US7262537B2 (en) * 2002-07-19 2007-08-28 Hamilton Sundstrand Corporation Electric motor and generator component having a plurality of windings made from a plurality of individually conductive wires
US20040012290A1 (en) * 2002-07-19 2004-01-22 Worley Andrew C. Electric motor and generator component having a plurality of windings made from a plurality of individually conductive wires
CN1937359B (zh) * 2003-11-28 2011-06-22 株式会社日立制作所 电枢绕组及使用该电枢绕组的旋转电机
EP1548913A2 (fr) 2003-11-28 2005-06-29 Hitachi, Ltd. Enroulement d'induit et machine dynamoélectrique comprenant celui-ci
KR101044420B1 (ko) 2003-11-28 2011-06-27 가부시끼가이샤 히다치 세이사꾸쇼 전기자 권선 및 그것을 사용한 회전전기
US20060028086A1 (en) * 2003-11-28 2006-02-09 Hitachi, Ltd. Armature windings and dynamo-electric machine using the same
EP1548913A3 (fr) * 2003-11-28 2008-03-05 Hitachi, Ltd. Enroulement d'induit et machine dynamoélectrique comprenant celui-ci
US20050116573A1 (en) * 2003-11-28 2005-06-02 Hitachi, Ltd. Armature windings and dynamo-electric machine using the same
US7368842B2 (en) * 2003-11-28 2008-05-06 Hitachi, Ltd. Armature windings and dynamo-electric machine using the same
US7346974B2 (en) * 2004-02-02 2008-03-25 Alstom Technology Ltd Method for producing a conductor bar of transposed stranded conductors
US7863795B2 (en) * 2004-02-02 2011-01-04 Alstom Technology Ltd Method for producing a conductor bar of transposed stranded conductors
US20050168096A1 (en) * 2004-02-02 2005-08-04 Alstom Technology Ltd Method for producing a conductor bar of transposed stranded conductors
US7876016B2 (en) * 2007-11-15 2011-01-25 Sundyne Corporation Stator winding method and apparatus
US20090127966A1 (en) * 2007-11-15 2009-05-21 Juha Saari Stator winding method and apparatus
EP2262079A1 (fr) * 2009-06-08 2010-12-15 Alstom Technology Ltd Barre d'enroulement de stator en forme de barre Roebel avec des têtes de bobines transposés
US10510464B1 (en) * 2017-12-20 2019-12-17 Essex Group, Inc. Continuously transposed conductors and assemblies

Also Published As

Publication number Publication date
JPS53123801A (en) 1978-10-28
BE865349A (fr) 1978-09-28

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